MRI-compatible 3D television and display system

ABSTRACT

A display system compatible with a magnetic resonance imaging (MRI) apparatus disposed in a magnet room for producing video images to a patient in an MRI magnet tunnel, the images having a three-dimensional (3D) effect. An MRI-compatible 3D display includes a display panel configured to generate optical images having 3D content, and RF and electromagnetic interference filtering. A Faraday cage encloses the display panel, and includes an optically transparent window panel having an electrically conductive mesh and a layer of transparent optically isotropic material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 13/725,339, filedDec. 21, 2012, which in turn claims priority from U.S. ProvisionalApplication No. 61/582,323, filed Dec. 31, 2011, and from U.S.Provisional Application 61/729457, filed Nov. 23, 2012, the entirecontents of which applications are hereby incorporated by reference.

BACKGROUND

The use of displays in a Magnetic Resonance Imaging (MRI) equipmentenvironment was first developed in the late 80's and early 90's, asdescribed in U.S. Pat. No. 5,412,419, 5,432,544, 5,627,902, and5,877,732.

The earliest form of three dimensional (3D) technology first appeared inthe movie industry at the end of the 19th century. The principal conceptof this technology is to recreate the way humans see depth in real life;through a phenomenon called “binocular fusion”. 3D TVs digitallyrecreate the perception of binocular fusion to give viewers an immersiveviewing experience with pictures that pop off the screen. With therecent release of new 3D TVs to the market, together with readilyavailable 3D movies and other content, it would be advantageous to bringthis new technology to patients in the MRI environment.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the disclosure will readily be appreciated bypersons skilled in the art from the following detailed description whenread in conjunction with the drawing wherein:

FIG. 1 is a schematic illustration of a 3D LCD monitor setup in an MRIsuite.

FIG. 2 is a diagrammatic cross-sectional view of an exemplary embodimentof a system for 3D display delivery in the MRI.

FIGS. 3A and 3B are cross-sectional diagrammatic illustrations of anexemplary embodiment of a 3D display. FIG. 3B illustrates featureswithin circle 3B of FIG. 3.

FIG. 4 is a diagrammatic depiction of a patient viewing a 3D displaywhile lying in an MRI bore.

DETAILED DESCRIPTION

In the following detailed description and in the several figures of thedrawing, like elements are identified with like reference numerals. Thefigures are not to scale, and relative feature sizes may be exaggeratedfor illustrative purposes.

A 3D TV and the human eye have a lot in common. Since our eyes arespaced slightly apart, the left and right eye sees images from aslightly different perspective. The human brain then combines the twoimages to create a 3D impression. A 3D TV works the same way. Twoimages—displayed from slightly different angles—are viewed through 3Dglasses and then combined by the brain to construct a 3D image

The first generation of 3D shutter glasses produced a 3D effect, inpart, with technology embedded in the glasses. 3D shutter glassesfunction just like a camera shutter. A 3D television, in synchronizationwith the 3D glasses, alternately flashes a 2D image to each eye througha liquid crystal layer embedded within each lens of the glasses. Theviewer's brain then combines the images flashed to each eye to create a3D effect. However, the use of 3D shutter glasses in an MRI magnet roomapplication is useless due to the electronics and battery existing inthe active shutter glasses.

The next generation FPR (Film Patterned Retarder) 3D relies ontechnology embedded in the television. FPR 3D glasses use a circularpolarized filter to present two images concurrently to each eye. FPR 3DTVs incorporate the FPR technology in which a polarized film is placedon the 3D television screen to effectively split the left and rightimages into interweaving odd and even lines onscreen, and along with the3D glasses which use circular polarization filters of opposite sense,separates the left and right images before they are delivered to thebrain. This technically halves the original resolution of 3D content toeach eye. The images are then combined by the brain to create the 3Dimpression. The applicant has recognized that this technology is idealfor use in MRI applications.

An LCD TV can be shielded to block the emission of electromagneticinterference (EMI) inside of the MRI room, to provide an MRI-compatibledisplay. For example, the front active part of the LCD TV may beshielded with a micro conductive mesh or laser aided conductive meshwhich is 30 micrometers thick and will not appear when viewed with thenaked eye. The entire LCD monitor will then be housed in a shieldedFaraday cage, with inputs for power and the video/audio signals (e.g.carried by fiber optics or by Wi-Fi signals).

FIG. 1 illustrates a typical component layout within the MRI suite. Inthis exemplary layout, the MRI magnet is disposed in the magnet room,with a patient table for positioning the patient in the bore of the MRImagnet 10. An MRI-compatible 3D display such as a large MRI-compatibleLCD display 100 is positioned on a wall in the magnet room at a positionselected to allow the patient in the MRI bore to observe the display,with the aid of a mirror. In this exemplary embodiment, theMRI-compatible 3D display is a display 100 which employs FPR technologyto provide a 3D effect when used with an appropriate set of goggles orglasses, with circular polarization filters of opposite sense throughwhich the image generated by the 3D display is viewed.

The control room includes the Technologist Station 20 for controllingthe MRI system. An FPR-compatible video source 22 capable of generatingsignals to produce the 3D image is placed in the control room, and itssignal is converted (e.g. through an HDMI-to-Fiber Optic Converter 24)to an optical signal carried on an optical fiber 26. The video sourcemay be, for example, a DVD player, HDTV receiver, a PC, etc. The opticalfiber is passed from the control room into the equipment room andthrough a waveguide 28 positioned in a penetration panel 30 to themagnet room and to the large MRI-compatible LCD display 100.Alternatively, in another embodiment, the video source signals may bebroadcast using a Wi-Fi broadband network, wherein a Wi-Fi repeater isused to transmit signals (e.g. from an antenna mounted to the magnetroom wall).

FIG. 2 illustrates the patient setup for the system in further detail.The patient wears the circular polarized passive glasses or goggles 40,with lenses 42 having circular polarization filters of oppositepolarization sense for the left and right eye, typically applied by afilter film, and through the use of a reflective mirror 44, can view the3D MRI-compatible display (e.g. a shielded 3D LCD TV) located on eitherend of the MRI bore (tunnel). The patient goggles 40 are configured tobe MRI-compatible and fabricated without magnetic materials.Alternatively, the circularly polarized filters can be built into thepassive goggles or applied to the mirror 44 into which the patient looksto see the display image. The patient goggles are typically fabricatedof a very thin layer of optically clear plastic on which the filters areformed, and, because of the thinness, do not affect substantially the 3Dimage quality.

In exemplary embodiments, the display 100 may be a large screen highdefinition 3D display or TV, utilizing LCD, LED or OLED technology (i.e.a 3D HD TV) and images generated by the display are relayed to thesubject via a reflective mirror applied to a rear surface of a substrateformed of optically isotropic material. Alternatively, this could be afront surface mirror.

In an exemplary embodiment for use in an MRI magnet room, the 3D TV ishoused in a non-magnetic Faraday cage to shield EMI. A clear conductivewindow overlay is specially made for the MRI 3D application utilizing FRtechnology, where it is optically clear or transparent and does notaffect screen polarization.

The process of making the conductive window for the display in oneexemplary embodiment uses a very fine conductive mesh laminated betweentwo layers of optically isotropic glass or plastic material in a waythat the edge of the mesh at the window edges is exposed. A conductiveadhesive such as silver epoxy is applied to the mesh and window edges.By applying the silver epoxy, all the window edges become shorted to themesh, increasing a surface area of conductive material in electricalcontact with the mesh. With the conductive window assembled in thehousing, the edge of the conductive window stays in tight contact withthe housing of the display. For the 3D system to operate properly, thebase material of any adhesive or other structures used to build thewindow may not cause interference with the polarization of the TV.Optically isotropic materials are used for the rf (radio frequency)conductive window on the display and the reflective mirror (i.e.materials having the same optical properties in all directions). Themesh may be sandwiched between the two layers of the window because themesh is very fine and to protect it from damage.

Another alternative for constructing the fine mesh is to start with asheet of conductive copper applied to a glass layer, and then etch awaymost of the copper, leaving only a very fine line in the shape of veryfine mesh. The etching may be done by a laser or other etchingtechniques.

FIG. 3A is a diagrammatic cross-sectional view illustrating features ofan exemplary embodiment of a 3D flat panel display 100 suitable for usein the magnet room environment of FIGS. 1 and 2. FIG. 3B illustratesfeatures within circle 3B of FIG. 3A. The display is constructed toprovide a Faraday cage 110 defined by non-magnetic, electricallyconductive materials. The Faraday cage 110 includes a front bezel orcover structure 112 which circumscribes the display panel area 114, andrear cover 116. The cover structure 112 may be fabricated of anon-magnetic electrically conductive material such as, by way of exampleonly, brass or aluminum. The rear cover 116 attaches to the back of thecover structure 112. The Faraday Cage 110 includes an internal mountingframe structure 120 which is positioned between the inside of the frontbezel portion 112A of the cover structure 112 and the rear cover 116.The rear cover and the internal mounting frame structure are alsofabricated of non-magnetic electrically conductive material, such asbrass or aluminum.

The internal mounting frame structure 120 and the cover structure 112are configured to support the planar display system components,including the LCD/LED/OLED display panel 130, an LED backlight panel 140(for an LCD implementation), and a mesh panel assembly 150 to cover thedisplay panel or window area 114. The display panel may be a flat paneldisplay such as an LCD (liquid crystal display) panel, an LED (lightemitting diode) panel, an OLED (organic light emitting diode) panel, oreven a plasma panel, for example. In the case of an LCD display panel,the backlight panel 140 is provided behind the display panel 130. Thebacklight panel 140 may be omitted for the implementation in which thedisplay panel is OLED.

The mesh panel assembly 150 in this exemplary embodiment includes planarlayers 150A and 1508 of transparent optically isotropic material, suchas a glass, which sandwich a non-magnetic, electrically conductive mesh150C. The opening size of the mesh is preferably sufficiently small soas to block RF signals from passing through, yet large enough to allowthe optical image rays pass through. An exemplary mesh opening size ison the order of 50 mesh openings per square inch. The mesh may befabricated from copper, tungsten or alloy thereof, for example. The meshpanel assembly 150 is constructed to be optically isotropic, i.e. with arefractive index not dependent on the polarization and propagationdirection of light. If the mesh panel assembly 150 were to beanisotropic, and exhibit birefringence, this could affect the polarizedlight emitted from the panel 130 and destroy the 3D effect. The panel150 could also be a single layer of optically isotropic material, onwhich the mesh is applied or etched. However, to protect the mesh fromdamage, sandwiching the mesh between two layers can be advantageous.High quality isotropic glass, and plastics such as isotropic acrylic andCR39, may be employed to form the window assembly 150.

In this exemplary embodiment, the display panel 130 is spaced from themesh panel assembly 150 by an elastomeric spacer member 122. An EMI(electromagnetic interference) gasket 124A is positioned betweenadjacent surfaces of the edge of the mesh panel 150 and the innersurface of flange portion 120A1 of the internal mounting frame structure120. Another EMI gasket 1248 is positioned between adjacent portions ofthe back edge 1128 of the cover structure 112 and the back flangeportion 120C1 of the internal mounting frame structure 120. The EMIgaskets can be fabricated of a springy non-magnetic, electricallyconductive material, such as a copper/bronze alloy.

The edges of the electrically conductive mesh layer 150C are broughtinto contact with the adjacent surface of the internal mounting framestructure 120, e.g. at 120D, so that the mesh is electrically connectedto the internal mounting frame structure 120. A grounding connection 180at the rear cover is connected to system ground within the magnet roomso that the Faraday cage 110 is grounded.

A support structure 160 is positioned between a back panel portion 1208of the internal mounting frame structure 120 and the lower portion ofthe LED backlight 140. The support structure 160 is fabricated of anon-magnetic material such as aluminum. The top edge of the LEDbacklight is secured by a bracket portion 120A2 of the frame structure120. A circuit board structure 170 is positioned with an upwardlyextending board portion 170A positioned between the display panel 130and the backlight panel 140. The board portion can include circuittraces for making electrical contact with the circuit of the displaypanel, for example. The particular technique for fabricating the displaypanel 130 and driving it to provide the 3D display images may beconventional.

An interface module 190 is positioned within the Faraday cage, adjacentthe rear cover 116, and provides a power supply for the 3D flat paneldisplay 100, and a connection (e.g. fiber optic, broadband Wi-Fi) forthe video source signals to be supplied to the 3D flat panel display100.

The 3D flat panel display 100 in this exemplary embodiment employs FPRtechnology to provide a 3D effect when used with an appropriate set ofgoggles or glasses, with circular polarization filters of opposite sensethrough which the image generated by the 3D display is viewed.Alternatively, the display could use left and right linear polarizationsto produce the 3D effects, with corresponding left and right linearpolarization on the polarized films applied to the goggles worn by thepatient. Other display technologies could produce the 3D effect inconjunction with electronics to create the 3D effect on the displayitself, without the need for the patient to wear polarized glasses. Forexample, parallax barrier, glasses-free displays are known, which workby placing an opaque screen door-like barrier over the screen. Each eyeviews the barrier from a slightly different angle, and therefore seesdifferent sets of pixels behind it. Some manufactures use an LCD barrierthat can be turned off to enable 2D viewing. In the case of the parallaxbarrier, glasses-free display, the patient might directly view the 3Dimage reflected from the mirror. In all cases, the optical path betweenthe image panel generating the 3D images and the patient's eyes shouldnot pass through birefringent materials, which may adversely affect the3D content of the images.

FIG. 4 diagrammatically illustrates how, in one exemplary embodiment, apatient in an MRI tunnel could view the 3D images generated by the 3Dflat panel display 100. The patient wears the circular polarized passiveglasses or goggles, with lenses having circular polarization filters ofopposite polarization sense for the left and right eye, typicallyapplied by a filter film, and through the use of a reflective mirror,can view the MRI-compatible display, e.g. a shielded LCD TV, located oneither end of the MRI bore (tunnel). The glasses are configured to beMRI-compatible, without magnetic materials. Alternatively, thecircularly polarized filters can be built into the passive glasses orapplied to the mirror into which the patient looks to see the displayimage. The patient can see the display while lying down on the MRI bore,using the combination of the polarized films in conjunction with thereflective mirror.

The reflective mirror 44 in the MRI bore is optically isotropic, i. e.with a refractive index not dependent on the polarization andpropagation direction of light. Typically, the reflective surface isplaced on a back side of the mirror substrate, to reduce chances ofscratching or damaging the reflective surface (as compared to formingthe reflective surface on the front face of the mirror substrate). Asuitable exemplary plastic for the mirror substrate is acrylic or CR39.For the case in which the reflective surface is placed on the backsurface of the mirror substrate, the light path is through thesubstrate, which in this case should be formed of an optically isotropicplastic material, to avoid affecting the 3D image content of the viewedimage. If the reflective surface is placed on the mirror front face,then the light path does not pass through the mirror substrate, and thesubstrate material should have little effect on the image quality.

Although the foregoing has been a description and illustration ofspecific embodiments of the subject matter, various modifications andchanges thereto can be made by persons skilled in the art withoutdeparting from the scope and spirit of the invention.

What is claimed is:
 1. A display system compatible with a magneticresonance imaging (MRI) apparatus disposed in a magnet room forproducing a video image to a patient in an MRI magnet tunnel, the imagehaving a three-dimensional (3D) effect, the system comprising: a videosignal source for producing video image signals; an MRI-compatible 3Ddisplay responsive to said video signals and disposed within said magnetroom for providing a 3D display within said magnet room, said displayincluding RF and electromagnetic interference filtering to prevent noisefrom said display from affecting the quality of the images produced bysaid MRI apparatus, the 3D display employing FPR (Film PatternedRetarder) technology to provide separate left and right eye images toprovide optical image rays having 3D image content; a mirror positionedin the MRI magnet tunnel and positioned so that the patient in thetunnel can view the 3D display; circular polarization filters ofopposite sense for each patient eye and positioned so the patient viewsimages generated by the 3D display and reflected from the mirror throughthe circular polarization filters to produce a 3D effect.
 2. The systemof claim 1, wherein the MRI-compatible 3D display comprises: a displaypanel for generating the optical image rays; and an opticallytransparent window panel through which the optical image rays pass, thewindow panel covered by a conductive mesh having a mesh opening sizesufficiently small to block rf signals generated by the display systemfrom passing through the mesh and large enough to allow optical imagerays from the display panel from passing through without, the window theoptically transparent window panel comprising an transparent opticallyisotropic material allowing optical image rays pass through withoutsignificantly affecting the 3D image content.
 3. The system of claim 2,wherein the window panel comprises at least one layer of saidtransparent optically isotropic material, and said conductive mesh isadjacent a surface of said layer.
 4. The system of claim 3, wherein saidat least one layer of said transparent optically isotropic materialcomprises a first layer and a second layer, and said conductive mesh issandwiched between said first layer and said second layer.
 5. The systemof claim 3, wherein a peripheral edge of the conductive mesh is exposedat a peripheral edge of the window, and wherein a conductive adhesive isapplied to the peripheral edge of the mesh and the peripheral edge ofthe window, such that with the window assembled in a conductive displayhousing, the edge of the window stays in tight electrical contact withthe housing.
 6. A display system compatible with a magnetic resonanceimaging (MRI) apparatus disposed in a magnet room for producing a videoimage to a patient in an MRI magnet tunnel, the image having athree-dimensional (3D) effect, the system responsive to video imagesignals and comprising: an MRI-compatible 3D display responsive to thevideo signals and disposed within said magnet room for providing a 3Ddisplay within said magnet room, said display including RF andelectromagnetic interference filtering to prevent noise from saiddisplay from affecting the quality of the images produced by said MRIapparatus, the 3D display employing FPR (Film Patterned Retarder)technology to provide separate left and right eye images to provideoptical image rays having 3D image content; a mirror positioned in theMRI magnet tunnel and positioned so that the patient in the tunnel canview the 3D display; and circular polarization filters of opposite sensefor each patient eye and positioned so the patient views imagesgenerated by the 3D display and reflected from the mirror through thecircular polarization filters to produce a 3D effect.
 7. The system ofclaim 6, wherein the MRI-compatible 3D display comprises: a displaypanel for generating the optical image rays; and an opticallytransparent window panel through which the optical image rays pass, thewindow panel covered by a conductive mesh having a mesh opening sizesufficiently small to block RF signals generated by the display systemfrom passing through the mesh and large enough to allow optical imagerays from the display panel from passing through without, the window theoptically transparent window panel comprising an transparent opticallyisotropic material allowing optical image rays pass through withoutsignificantly affecting the 3D image content.
 8. The system of claim 7,wherein the window panel comprises at least one layer of saidtransparent optically isotropic material, and said conductive mesh isadjacent a surface of said layer.
 9. The system of claim 8, wherein saidat least one layer of said transparent optically isotropic materialcomprises a first layer and a second layer, and said conductive mesh issandwiched between said first layer and said second layer.
 10. Thesystem of claim 8, wherein a peripheral edge of the conductive mesh isexposed at a peripheral edge of the window, and wherein a conductiveadhesive is applied to the peripheral edge of the mesh and theperipheral edge of the window, such that with the window assembled in aconductive display housing, the edge of the window stays in tightelectrical contact with the housing.